Deployable ramp assemblies for vehicles, for example deployable wheel chair ramps for buses, exist in a variety of configurations. Examples include ramp assemblies with a deployable portion which is slidable in and out of a space defined under a fixed ramp portion, and ramp assemblies with a pivotable portion pivoting up to more than 180° from a stowed position against the fixed portion. Typical drive mechanisms for such ramp assemblies, e.g. gear mechanisms, chain drives, belt drives, and combinations thereof, are usually relatively complex, with a number of movable parts that may become disengaged, jammed, misaligned, etc. during use.
Accordingly, improvements are desirable.